Hobbyist and decorators have pursued the objective of enhancing the appearance and enjoyment of aquariums and fish tanks in various ways for many years. The equipment provided is varied and multifaceted to provide unusual visual effects.
It is well recognized that it is entertaining and visually stimulating to watch the operations of an aquarium and the motion of the fish and other aquatic life moving in the atmosphere of green life, water, and lighted reflections. Novel enhancements to these perceptions have been sought and are well recognized and valuable and useful to the viewer as well as to those in the business of providing components to the construction and operation of aquariums.
One visual effect that has been pursued is the provision of passages and compartments as exemplified by the following U. S. Patents:
U.S. Pat. No. 4,044,721 Foley et al. discloses a fish tank construction which is made with interior partitions through which the fish can swim into simulated rooms in a simulated house.
U.S. Pat. No. 3,991,715 Gibson Jr. reveals an aquarium with an arch channel, or bridge, over which the fish can swim. The bridge channel is semicircular and includes a magnifying glass at the top of the bridge to give a larger view of the fish. The bridge can go from one aquarium to the next (see FIG. 4).
U.S. Pat. No. 3,921,583 De Shores shows fish channels from one aquarium end tank to another. U.S. Pat. No. 3,903,844 Greenia describes an aquarium with various angled bridge channels having a triangular cross-section.
U.S. Pat. No. 2,512,678 Rice discloses a fish bowl with an over-the-top molded channel. U.S. Pat. No. 2,059,927 Beck reveals an early version of a bridge channel showing gates for filling purposes (see FIG. 6).
U.S. Pat. No. 1,943,417 Bringman shows a crown attachment for aquarium tanks in which the fish swim up over a bridge. U.S. Pat. No. 1,576,462 Polzin contains a early disclosure of the general concept of fish bridges.
This invention is directed to those aquatic bridges which span from one surface of water or tank to another.
The prior art devices have been difficult to install and maintain for various reasons. One problem or difficulty is filling the bridge with water and maintaining the bridge completely full so that there is a complete path of water for the fish to swim from one end of the bridge to the other. Naturally, if the water does not completely cross from one end of the bridge to the other in sufficient depth for the fish to swim all the way across, the device has loss its primary usefulness and attractiveness. In the prior art devices it has been apparently necessary to fill the bridge in the inverted position in the manner of filling a "U-shaped" tube which naturally seeks an equal level in both upward extending legs of the device. When the device has been filled then it must be inverted and placed into the aquarium without losing the filled water from the legs. U.S. Pat. No. 2,059,927 is representative of this. The bridge, in normal operation, is maintained full by the vacuum created at the inner, uppermost segment of the bridge. If the water in one leg or the other can flow out, the vacuum will be broken as pressure will reach the "vacuum" segment.
In order to overcome these problems this invention provides at least one of the combination of several construction features. One feature is the provision of watertight caps on the ends of the device which are closed while the device is filled.
The other feature is the provision of a vacuum release vent and/or capping means at the operational vacuum segment.
By means of these features, the filling and installation operation is greatly simplified.